AGN Jet Power, Formation of X-ray Cavities, and FR I/II Dichotomy in Galaxy Clusters

We investigate the ability of jets in active galactic nuclei (AGNs) to break out of the ambient gas with sufficiently large advance velocities. Using observationally estimated jet power, we analyze 28 bright elliptical galaxies in nearby galaxy clusters. Because the gas density profiles in the innermost regions of galaxies have not been resolved so far, we consider two extreme cases for temperature and density profiles. We also follow two types of evolution for the jet cocoons: being driven by the pressure inside the cocoon (Fanaroff-Riley [FR] I type), and being driven by the jet momentum (FR II type). Our main result is that regardless of the assumed form of density profiles, jets with observed powers of ~ 10^{44} erg s^{-1} are less affected by the ambient medium, and some of them, but not all, could serve as precursors of the FR II sources.